Resolution (chromatography)

In chromatography, resolution is a measure of the separation of two peaks of different retention time t in a chromatogram.

Expression
Chromatographic peak resolution is given by


 * $$R_s = 2\cfrac{t_{R2}-t_{R1}}{w_{b1}+w_{b2}} $$

where tR is the retention time and wb is the peak width at baseline. Here compound 1 elutes before compound 2.

If the peaks have the same width


 * $$R_s = \cfrac{t_{R2}-t_{R1}}{w_b} $$.

Plate number


The theoretical plate height is given by


 * $$H = \frac{L}{N} $$

where L is the column length and N the number of theoretical plates. The relation between plate number and peak width at the base is given by


 * $$N = 16 \cdot \left(\frac{t_R}{W_b}\right)^2 \,$$.